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Biomedical subjects

S Sekine

Publications and source records attributed to S Sekine.

At least 73 records · Page 4Linked to original sources
PubMed1995

Novel homogeneous enzyme immunoassay: chitinase activity enhancement immunoassay (CAEIA).

A novel homogeneous enzyme immunoassay has been developed that takes advantage of the observation that the activity of a bacterial chitinase could be enhanced by the binding of a ligand conjugate of a monoclonal antibody to the enzyme (L-MAbchi). The enhancement was suppressed by an antiligand antibody (AbL). Free ligand molecules competed for AbL combining with L-MAbchi, and the suppression of the enhancement was reduced. Thus the concentration of free ligand could be estimated. Biotin was used as a ligand in this model experiment. When this monoclonal antibody was conjugated with a ligand (e.g., biotin), we furthermore found that the enhancement could be suppressed by an antiligand antibody (AbL). When free ligand molecules are added to the system, competition with L-MAbchi results to reduce the suppression of enhancement.

Acetylglucosaminidase↗
PubMed1995

Preliminary evidence suggesting variations of GtH 1 and GtH2 mRNA levels at different stages of gonadal development in rainbow trout, Oncorhynchus mykiss.

To study the variations of alpha and beta GtH 1 and 2 gene expression during gonadal development in male and female rainbow trout, chum salmon alpha and beta GtH 1 and 2 probes were used. The alpha subunit cDNA probe used is identical to the cDNA encoding the alpha subunit common to both GtH 1 and 2. Total RNAs were prepared from pooled pituitaries and the validation of the use of these probes for studying the variation of GtH mRNAs was made by Northern blot analysis. The quantitative determination of GtH mRNAs employed slot blot hybridization. In males and females, beta GtH 1 predominates in early stages of gonadal development (spermatogonia A and previtellogenesis), beta GtH 2 being weakly expressed. Both beta GtH 1 and beta GtH 2 are expressed during prespermiation, spermiation, and the periovulatory period with a predominance of beta GtH 2. In both sexes alpha GtH variations follow beta GtH 2 variations.

Animals↗
PubMed1995

Dacron coronary graft obstruction after composite graft replacement of aortic root.

Obstruction of the left coronary ostial anastomosis is a rare late complication after composite graft replacement of the ascending aorta and the aortic valve with separate Dacron coronary grafts. Intimal proliferation caused by the turbulent blood flow at this site may be the cause of the obstruction, which is considered a possible cause of late cardiac events such as sudden death and global myocardial infarction. We describe a case of tight stenosis at the left coronary ostial anastomosis in a 38-year-old woman with Marfan's syndrome who had undergone a composite graft replacement that employed separate Dacron coronary grafts.

Adult↗
PubMed1995

cDNA cloning and characterization of human glyoxalase I isoforms from HT-1080 cells.

We have isolated two kinds of cDNA clones encoding glyoxalase I from a human fibrosarcoma HT-1080 cDNA library. One of them is identical to the glyoxalase I cDNA isolated by us, and the other encodes a protein in which alanine at position 111 of the reported sequence for glyoxalase I is replaced by glutamic acid. When the two cDNAs were co-translated in vitro, three bands representing two homodimers and one heterodimer appeared on native polyacrylamide gel electrophoresis, as observed for glyoxalase I purified from human erythrocytes or derived from a HT-1080 cell lysate. Escherichia coli cells carrying an expression vector of one of the novel glyoxalase I cDNAs showed glyoxalase I activity. These results reveal that two isoforms of human glyoxalase I showing different electrophoretic properties result from a change in one amino acid residue.

Blotting, Northern↗
PubMed1995

[Squamous cell carcinoma of the ureter as a late complication of ureterocutaneostomy--a case report].

A case of squamous cell carcinoma of the ureter was reported. A 62-year-old woman, who underwent left nephrectomy and right ureterocutaneostomy at the age of thirty-one because of tuberculosis of the urinary tract, visits our hospital periodically for an ureteral catheter change. An urgent nephrostomy was performed because of ureteral stricture on March 8, 1994. Three months later tenderness and induration appeared at the former ureteral stoma. The resected specimen was histologically diagnosed as squamous cell carcinoma. Right palliative ureterectomy did not produce the desired effects due to the invasion of the tumor into the surrounding organs. In this rare case, it is suggested that chronic infection and irritation of the indwelling catheter might be causative of squamous cell carcinoma of the ureter.

Carcinoma, Squamous Cell↗
PubMed1995

[Evaluation on the perioperative left ventricular function of aortic valve replacement in patients with chronic aortic regurgitation].

To evaluate the perioperative left ventricular function in 36 patients undergoing aortic valve replacement (AVR) in patients with isolated chronic aortic regurgitation (AR), hemodynamic variables before and within the first 24 hours and one month after operation were measured with Swan-Ganz catheter and echocardiography. The patients were divided into two groups based on preoperative left ventricular end-systolic volume index (LVESVI): 5 patients had a LVESVI of 90 ml/m2 and greater (group I), 31 had a LVESVI smaller than 90 ml/m2 (group II). Left ventricular dimension at end-diastole and end-systole, left ventricular end-diastolic volume index at one month after operation significantly decreased in comparison with that of preoperation. However, left ventricular ejection fraction in the two groups were not improved, and left ventricular mass index in group I did not decreased. On the other hand, changes of cardiac index, stroke volume index and left ventricular stroke work index within the first 24 hours after operation were not significantly different between the two groups. The incidence of postoperative premature ventricular contraction in group I was significantly higher than that of group II. However, there was no difficult problems in postoperative management of the two groups. It is suggested that AVR in AR with left ventricular dysfunction can safely be operated and its postoperative management is similar to AVR in AR with no left ventricular dysfunction.

Adult↗
PubMed1994

Construction of a human full-length cDNA bank.

We aimed to construct a full-length cDNA bank from an entire set of human genes and to analyze the function of a protein encoded by each cDNA. To achieve this purpose, a multifunctional phagemid shuttle vector, pKA1, was constructed for preparing a high-quality cDNA library composed of full-length cDNA clones which can be sequenced and expressed in vitro and in mammalian cells without subcloning the cDNA fragment into other vectors. Using this as a vector primer, we have prepared a prototype of the bank composed of full-length cDNAs encoding 236 human proteins whose amino acid sequences are identical or similar to known proteins. Most cDNAs contain a putative cap site sequence, some of which show a pyrimidine-rich conserved sequence exhibiting polymorphism. It was confirmed that the vector permits efficient in vitro translation, expression in mammalian cells and the preparation of nested deletion mutants.

Animals↗
PubMed1994

Characterization of monoclonal antibodies to chitinase A1 and enhancement of chitinase A1 activity by monoclonal antibodies.

A total of eleven hybridomas which secrete antibodies against chitinase A1 were established. Among the eleven monoclonal antibodies (MAbs) obtained, six recognized the catalytic domain, three recognized the type III region and two recognized the chitin binding domain of chitinase A1. Of the two MAbs which recognized the chitin binding domain one was found to also react with chitinase D, but none of the other MAbs which recognized either the type III region or the chitin binding domain reacted with chitinase D despite the extensive amino acid sequence similarity between both the type III and chitin binding domains of the two chitinases. Two of the eleven MAbs enhanced chitinase activity significantly, while the other MAbs did not have any significant effect on chitinase A1 activity.

Animals↗
PubMed1994

Long-term results of primary closure for ventricular septal defects in the first year of life.

The long-term results of primary closure for large ventricular septal defects (VSDs) in infants under 1 year of age with severe symptoms were studied over a period of more than 10 years. Between January, 1971 and March, 1982, 49 infants underwent primary closure of a VSD through a right ventriculotomy using complete cardiopulmonary bypass with mild hypothermia. There were four hospital deaths but no late deaths. Two of four infants with residual shunts had a left ventricular-right atrial shunt which necessitated reoperation. Surgical heart block occurred in two infants who recovered sinus rhythm in the late period. The cardiothoracic ratio decreased from 60.5% preoperatively to 50.6% in the late postoperative period. Examination by cardiac catheterization revealed that the pulmonary-to-systemic pressure ratio (Pp/Ps) of 23 patients with a Pp/Ps of over 0.75 fell from 0.89 +/- 0.09 preoperatively to 0.42 +/- 0.12 by 1 month postoperatively, then to 0.27 +/- 0.05 in the late postoperative period. The latest values for the cardiac index and left ventricular ejection fraction were 3.4 l/min per m2 and 64.4%, respectively. More than 10 years after their operation, all the survivors were growing normally and maintaining a good quality of life, which supports our recommendation that primary repair should be performed in the first year of life for infants with large VSDs.

Bundle-Branch Block↗
PubMed1994

The roles of the C-terminal domain and type III domains of chitinase A1 from Bacillus circulans WL-12 in chitin degradation.

The mature form of chitinase A1 from Bacillus circulans WL-12 comprises a C-terminal domain, two type III modules (domains), and a large N-terminal domain which contains the catalytic site of the enzyme. In order to better define the roles of these chitinase domains in chitin degradation, modified chiA genes encoding various deletions of chitinase A1 were constructed. The modified chiA genes were expressed in Escherichia coli, and the gene products were analyzed after purification by high-performance liquid chromatography. Intact chitinase A1 specifically bound to chitin, while it did not show significant binding activity towards partially acetylated chitosan and other insoluble polysaccharides. Chitinases lacking the C-terminal domain lost much of this binding activity to chitin as well as colloidal chitin-hydrolyzing activity. Deletion of the type III domains, on the other hand, did not affect chitin-binding activity but did result in significantly decreased colloidal chitin-hydrolyzing activity. Hydrolysis of low-molecular-weight substrates, soluble high-molecular-weight substrates, and insoluble high-molecular-weight substrates to which chitinase A1 does not bind were not significantly affected by these deletions. Thus, it was concluded that the C-terminal domain is a chitin-binding domain required for the specific binding to chitin and that this chitin-binding activity is important for efficient hydrolysis of the sufficiently acetylated chitin. Type III modules are not directly involved in the chitin binding but play an important functional role in the hydrolysis of chitin by the enzyme bound to chitin.

Amino Acid Sequence↗
PubMed1994

Astrovirus as a cause of gastroenteritis in Japan.

We used an enzyme immunoassay (EIA) to screen for astrovirus in stool specimens from outbreaks and sporadic cases of gastroenteritis collected between 1982 and 1992 in six prefectural public health institutes in Japan. Three outbreaks of gastroenteritis involving schoolchildren and adults were confirmed to be attributable to astrovirus. Astrovirus was detected in 6 to 10% of the specimens from patients with sporadic gastroenteritis from whom no other bacterial or viral agent had been identified. Among the sporadic cases, astrovirus was most frequently detected in infants less than 1 year of age, and the incidence peaked in March and April. Using specimens from recent outbreaks, we found that the EIA was more sensitive than electron microscopy (EM) for the detection of astrovirus, and many EM-negative specimens were positive by EIA. However, some stool specimens previously found to have astrovirus-like particles by EM were negative by EIA, perhaps because of inadequate storage conditions, such as long-term storage and repeated freezings and thawings. Our results indicate that astrovirus is more commonly associated with childhood gastroenteritis than has been previously appreciated and suggest that further studies to examine the epidemiology and disease burden of this virus are needed.

Adolescent↗
PubMed1994

[Aortic dissection with giant pseudoaneurysm as a rare late complication of aortic valve replacement--a case report].

A 60-year-old man who had received aortic valve replacement for aortic regurgitation at 47 years of age developed sudden syncope and shock on Mar. 28, 1991. Close examination including CT scan and aortography revealed DeBakey type I aortic dissection with giant pseudoaneurysm which compressed superior vena cava and right pulmonary artery and caused superior vena cava syndrome. He underwent elective ascending aortic replacement under profound hypothermic cardiopulmonary bypass and circulatory arrest on Jun. 17, 1991. The giant pseudoaneurysm was present posterolaterally to the ascending aorta. It communicated with the false lumen and contained massive thrombi. The intimal tear of the ascending aorta existed along the suture line of previous aortotomy.

Aortic Dissection↗
PubMed1994

[Adjunctive methods for surgery of descending thoracic aortic aneurysm].

During the last 6 years, we employed partial extracorporeal circulation (PEC) in 7 cases and left heart bypass (LHB) in 9 cases as adjunctive methods for surgery of descending thoracic aortic aneurysm. During the aortic clamping, systemic heparinization was performed to keep an ACT more than 400 seconds in a PEC group, while it was kept from 200 to 250 seconds in LHB group. The bypass flow was controlled to maintain the distal arterial pressure over 50 mmHg in both groups. Hemodynamics during the aortic clamping were stable in both groups and significant differences were not found between them. However, ventricular fibrillation occurred in one case of LHB group, who suffered from coronary artery disease, and required subsequent PEC to maintain systemic circulation. Both PEC and LHB provided adequate intraoperative hemodynamics and postoperative serum biochemistries. But we preferred to adopt PEC to maintain the diatal perfusion in cases with heart disease, who are likely to develop circulatory deterioration under the aortic clamping.

Adult↗
PubMed1994

Cloning and characterization of human type 2 and type 3 inositol 1,4,5-trisphosphate receptors.

We have cloned cDNAs coding for human type 2 and type 3 and part of type 1 inositol 1,4,5-trisphosphate receptors (IP3Rs). The complete nucleotide sequences for type 2 and type 3 receptors were determined and the pharmacological properties of the latter were characterized. Human type 2 and type 3 IP3Rs are 2701 amino acids and 2671 amino acids long, respectively, and have significant sequence homologies as well as structural similarities including the six membrane-spanning regions near the C-termini when compared with the rat or mouse counterpart. COS-7 cells transfected with human type 3 IP3R showed characteristic inositol 1,4,5-trisphosphate (IP3)-binding properties with Kd values of 28.8 nM. The order of potency of competition with IP3 was Ins(1,4,5)P3 (IP3) > Ins(2,4,5)P3 > Ins(1,3,4,5)P4 > Ins(1,2,3,4,5,6)P6. Type 2 and type 3 IP3Rs were mapped to human chromosomes 12p11 and 6p21, respectively, by in situ hybridization. cDNA cloning of the human IP3Rs allowed us to identify the types of the receptor expressed in various human hematopoietic and lymphoma cell lines. The type 3 receptor was present in all of cell lines tested, while the type 1 or 2 receptor was expressed in only particular cell types. The differential expression of the IP3R types could confer the cell-specific regulation on the IP3/Ca2+ signalling.

Amino Acid Sequence↗
PubMed1994

[Total aortic replacement in a patient with extensive thoracoabdominal aortic aneurysm--a case report].

A 35-year-old woman with a form fruste of Marfan's syndrome, presented the extensive thoracoabdominal aortic aneurysm. CT scan, MRI and aortogram revealed that she had a true aneurysm of ascending aorta and aortic arch and chronic DeBakey IIIb dissecting aneurysm extending throughout the descending thoracic and abdominal aorta. The surgical treatment was consisting of two staged operations. At the first operation, ascending aorta and aortic arch were reconstructed under cardiopulmonary bypass and selective cerebral perfusion. Elephant trunk method was employed for the second operation. The second operation was performed by graft replacement of the entire descending thoracic and abdominal aorta with reattachment of intercostal and visceral arteries. She discharged the hospital without any complication including paraplegia.

Adult↗
PubMed1994

[Conduction disturbances after coronary artery bypass grafting with retrograde cardioplegia].

We studied forty-six cases, who had undergone coronary artery bypass grafting with retrograde cold blood cardioplegia for myocardial protection, to manifest the frequency and causative factors of postoperative conduction disturbances. We obtained the following conclusions. 1) Postoperative conduction disturbances developed in nineteen cases (41.3%), all of which were right bundle branch blocks, but these were usually transient and were not associated with further complications in the follow-up period. 2) There were no significant differences in many factors, including number of grafts, aortic cross-clamp times, or peak CK-MB between cases with and without postoperative conduction disturbances.

Adult↗
PubMed1993

Expression cloning of a novel Gal beta (1-3/1-4) GlcNAc alpha 2,3-sialyltransferase using lectin resistance selection.

This report describes the isolation of a cDNA encoding a novel human Gal beta (1-3/1-4)GlcNac alpha 2,3-sialyl-transferase involved in the biosynthesis of the sialyl Lewis x determinant (NeuAc alpha 2-3 Gal beta 1-4(Fuc alpha 1-3)GlcNAc). A cDNA library of the human melanoma cell line WM266-4 was constructed in an Epstein-Barr virus-based cloning vector. Selection of the B-cell line Namalwa expressing transfected cDNAs in the presence of the cytotoxic lectin Ricinus communis agglutinin 120 gave a cDNA encoding a protein with type II transmembrane topology, as found for mammalian glycosyltransferases. The use of this lectin, which is specific to galactose residues (especially the Gal beta 1-4GlcNAc structure), originates from our prediction that the modification of the Gal beta 1-4GlcNAc structure (a backbone of the sialyl Lewis x structure) by glycosyltransferases may increase the levels of resistance to this lectin. Comparison of this cDNA sequence with those of three other cloned sialyltransferases revealed two conserved regions shared by all four enzymes. Expression of the COOH-terminal catalytic domain of this protein showed alpha 2,3-sialyltransferase activity with substrate specificity different from that of CMP-N-acetylneuraminate:N-acetyllactosaminide alpha-2,3-sialyltransferase (Gal-beta 1-3(4)GlcNAc alpha 2,3-sialyltransferase, EC 2.4.99.6). Furthermore, expression of this cDNA in Namalwa cells increased the level of sialyl Lewis x antigens. The cloning approach based on lectin resistance may be useful for the isolation of cDNAs encoding other mammalian glycosyltransferases.

Amino Acid Sequence↗